Nutrient source in pico

[Mihai]

I have a 0.5 gal pico with corals only. It looks like it suffers from heavy nutrient input (cyano and other film algae in large quantities) although I syphon quite a bunch every week, do a 50% water change and I don't feed anything during the week...

The tank is acrylic with a very small HOB filter and a 19W 6500K bulb...
It sits in the kitchen very far from the stove, so no spills of food. I am using RO/DI water with a TDS 0-1.

Thanks for any ideas on the source of the nutrients,
Mihai

 

[Anonymous]

Circulation, circulation, circulation. What do you have for circulation, i.e. powerhead, pump, etc.? A HOB filter doesn't do it in my experiences.

Regards,
David Mohr

 

[Mihai]

It's a red sea nano filter. It says 60-90 LPH = 15 - 22 GPH. For a 0.5 pico this is huge flow. I have nothing restricting the flow (open to the maximum and no media, not even LR). I have some montiporas (capricornis and digitata) doing well (growing slowly although they got brown due to relatively low light) and an acro that started encrusting (after loosing color as well). If those are holding, I'd guess that there is some flow. Perhaps not enough.

The main question is: it seems that I'm pulling something out every week (the cyano and algae) without putting anything back in. Where does it come from (it doesn't obey the conservation of mass ) ?

Thanks,
Mihai

 

[aquariumgirl]

With the pico I have I do a 50% waterchange everyday using water from the bigger tank. I think b/c the skimmer makes a huge difference in water quality. I still get a little brown algae but no cyano.

 

[Anonymous]

Mihai,
Kitchens have a way of "collecting" dust, grease and food scraps. I know in my kitchen, regardless how much I clean it, stuff seems to find it's way all the way across the room, and it's a honkin big kitchen. Maybe just a change in location will help.

 

[Mihai]

I used to do changes with water from the display as well, and I thought that the nutrients come from the display, that's when I started doing changes with fresh seawater.

I'll try change the location of the pico see what happens.
Thanks,
M.

 

[tinyreef]

even a small amount of biomass can produce a large amount of cyano. the cyano is also photosynthetic so it really doesn't need all that much nutrient to keep going.

corals also hold energy reserves and give off some, e.g. coral slime. the system still takes in CO2 and light so the photosyns are still doing their job (good thing too) so i would think it's more of what david was saying plus a touch of the lighting that's promoting the cyano.

some of the film crud could be the same and/or the need for breaking water surface tension.

 

[Mihai]

It's likely something like you're saying: light + some gasses disolved = cyano. Probably circulation would prevent the cyano. I'm trying to avoid extra pumps for esthetic reasons. I'll try increasing the light first. If it's not working, I'll consider a closed loop.

M.

 

[brandon4291]

I agree with DMohr and the rest of the crew's input. I might also add that 50% changes need to be done very regularly in order to outflow the small but significant (relative to volume) waste accumulations in the established pico reef. Established is the key word, new ones will run for a few months with less-than-acceptable cleaning regimens, but primary producers rear their ugly head eventually thanks to nutrient accumulation from the sources mentioned.

I do 100% changes on mine, not with established tank water but with clean/new SW weekly like clockwork if I can, to get over that eventual two-year mark and still have an algae-free zone. I used to do 100% bi-weekly and this wasn't sufficient in time--although not precise, this is ~equivalent to your 50% changes and that didn't cut it for me, especially after the system aged somewhat. I did three separate systems like this all for over a year, two with sand bottoms and one without, and I'm convinced the changes weren't large or frequent enough based on my (our) stocking preferences.

100% weekly is doing the trick now but I have also addressed stocking parameters and substrate parameters in order to catch and cause detritus as little as possible. I've been out of town before and skipped a week, once, and that didn't seem to hurt. I know your tank is stocked densely too and aged in terms of a small pico so that's why this work is needed IMO. We could cut down the density a bit, and maybe get by with 100% bi-weekly/50% weekly, but what's the visual fun in that? In the end you still want a dense/bright system that is 'clean' just like your large reefs

I would also recommend you up the cleaning intensity and scheduling and give it two months for full effect. In typical systems, the recovery from eutrophication is much slower than the onset of!

 

[Mihai]

Brandon, thanks for the advice.

I do the 50% water changes weekly (and regularly - never skipped one in the last 2 months). I also use freshly prepared saltwater (actually I prepare like 4 gallons at a time and store it in several 2 liter coke bottles for several weeks in a dark place).

I'm not sure why you say that my pico is stocked heavily - it only has corals - I thought that this is the minimum stocking load. On top of that I don't feed anything, although I wonder if this is good for the corals - some zoanthids don't seem to be thriving although others multiplied like crazy. BTW - do you have anything else in the pico and do you feed it? What and how much?

It is true that when the tank was new I didn't do the clockwork water changes (as it didn't seem to need it).

I upped my light (from 19W to 19W + 21W) last week, but for now nobody seems to care about that. I'll try to upgrade my flow by installing a larger HOB filter (a powerhead in a 0.5 pico would be hideous).

 

[brandon4291]

That's very good information to further our guesses on the controls and input of nutrients into your pico. I think a minor role could be played by not adhering to the water changes during the intial phase of the reef, but this is not catastophic and can be fixed with patience. IMO if you have any substrate, this would be a time of storing up a few initial bits of protein and detritus to start the episodes we see now. The LR (which also catches and stores waste particulate matter depending on circulation and cleaning habits) and various surfaces might have tiny/miniscule population blooms of whatever benthic microorganisms enjoyed this surplus--> as they dieoff and re-emerge based on nutrient availability, seeking population equilibrium, I think this is also played a role in the acitivity you see today. In my opinion, this is a further cycling of live rock to be selective for the environment at hand... in your case a mighty small one! I don't have any hardcore written experimental data to back all this up it's just what I gather from my slew of picos over the years.

It is true that coral-only systems have the lowest continual bioload, and IMO don't even count as bioload in larger nanos and reefs (due to dilution, can you believe we are using that word in the context of nano-reefs!) but in our sub-gallon picos they really do have comparable nitrate accumulation trends to fish-laden larger systems for a given amount of time... in other words, coral-only picos accumulate waste too, just in very 'trace' amounts relative to what it would take to tip the nitrate scales in say a 10 or 20 gallon reef tank. Most keepers time their water changes to the nitrogen accumulation maximums, and in all my picos I tended to reach them in a week's time even with minimal feedings. I also found partial water changes weren't enough to export that based on accumulation rates IMO. What I used to think was an acceptable nitrate range was also too much (I let it get up to 20 ppm usually)-now I'm super strict in the hopes of keeping this rascal alive and clean for years. Only time will tell@


I think rcsheng summed it up best with his reply, incorporating DMohr's circulation mention, that there are still protein liberations and subsequent ammonia/nitrogen cycle activities going on in the aged pico reef which is where your nutrients are stored and being released into those cyano mats...

Also, by 'feeding' I also don't mean literally feeding pellets to shrimp or other animals, it could be feed/protein support as introduced by those that don't dose their systems but add water from established reef systems, ie used water (but still cleaner than old pico water). Fresh/new SW is protein-free or as close to it as we'll get...and I think the use of it affords the longest interval time in between water changes, if nitrate clearance is the standard (other popular water change indicators for typical reefs could be micronutrients consumed where the wc replaces them).

I don't feed my tank any more than once per week, and its a mighty small portion. I use a small bit of DT's reef eggs, for their protein, and switch it out with cyclopeeze from time to time. I add DT's also once per week in small drops. In my experience, even the small but regular feedings that a shrimp would require were making my bioload too high for the coral density I desire and water change regularity I had in mind

**With every assumption or inference drawn there is always a good counter-point, and I'd like to mention those crazy $80-$400 eco-globes as such. They house 3 or 4 of those hawaiian red shrimps for years and get no additional protein input except for the tiny amounts found in the microalgae they consume... The systems rarely crash due to eutrophism, don't have sources of fresh iodine (as is commonly thought required in our reefs) and the darn shrimp usually exhaust their complete lifespans in those no-touch glass buggers while all along we walk the finest lines trying to delicately keep just one tiny shrimp alive for months. IMO those systems are ultra-low bioload and slow down all these above processes to the point one can get 12-36 months off a single volume of water and still keep the organisms kicking. They could not get that with coral, even that would speed up the bioloading too much for this type of pure hands-off approach.

 

[brandon4291]

Also, I don't want to give the impression there is only one way to succeed long-term with these things, you guys know that isn't the case. The fact that aquariumgirl changes almost everyday with the aged water takes these waste trends in her pico and stabilizes them closely to that of the addition water...if her primary reef is doing fine, the pico should too under these conditions. Now that is some water change discipline so using that method could work well and might even be better, because nutrient levels are consistent and never overdone with this change approach.

I was also talking about your stocking levels Mihai because I thought I recalled a picture of yours stocked very thick with corals which in time makes these things rather significant. If it's not that dense, I think some elements of the above are still at work because we are dealing with the manifestation of algae in one form or another.

 

[Mihai]

Brandon, I appreciate taking the time. I will keep the maintenance and up the circulation to see what happens. Regarding pictures of my pico, you must be confusing me with somebody else: I was never proud enough of the pico to display them.

I do have a 1/4" sand-bed and a hunk of LR. Actually, I'll take a pic and post it tomorrow if I get around it. You know, I never measured my nitrates... how come it never crossed my mind?

I have a 90gal display and a 10gal nano that are doing great. This 0.5 is really hard! I enjoy the challenge though.

Thanks a lot for the advice,
Mihai

 

[Mihai]

OK, I measured the nitrates. ZERO after one week after water change. It's expected (after 10 50% water changes!), but where is the cyano coming from?

M.

 

[brandon4291]

Wow Mihai, let me think on it for a sec. If the test is accurate for nitrate-nitrogen that is sure strange (O NO3) for a sandbedded system with age, but that also speaks well of the nutrient loading. Are those little gas bubbles in the front part of the sand bed? The sandbed looks clean, as in no dark pockets or brown concentrations I can see, but the gas (if that's what it is) signals some sort of respiration maybe-- possibly it gets some front light? like maybe from a bedroom window or something... I've had rather clean sandbeds (less detritus) produce little bubbles when lit from the front by a palm light...I guessed it was collections of photosynthetic oxygen (from algae photosynthesis) and small concentrations of waste gasses like CO2 liberated by bacterial respiration. Just brainstorming over your setup.

One thing about it, the picture helps greatly. That overage of algae you have is just the strain I get with my newer pico setups. A light brown film on the glass that's easily removed w water change, but prolific enough to be a headache. Usually goes away when cycling is complete/I fully think the system can recover since you aren't dealing with hair algae patches. I will go back and re-read your carbonate dosing approach, in the mean time would you get a morning pH reading for me and an evening (just after lights off) pH reading? We will get that issue solved eventually. I also want to wait for a least two weeks with your new circulation and water change (I'd still do it so we can start to eliminate variables) schedules to see what that adjusts. Worst case scenario it's extra work, but certaily won't hurt as a system test.

 

[brandon4291]

I can surmise a decent bit of your calcium and carbonate support through the coralline on the back wall and the plating of your sps acropora and monti's. Looks good. Let me also ask you about that reef rock you are using, if you were to take it out and mash your thumb with medium pressure along the top and sides, could you work off some mush from the rock on any part of it? It would look like brownish mud or sandy mud, I want to address the porosity and integrity of that major source of surface area in your system. Also, if you were to take the rock out of the system and soak it in clean sw in another bowl, would detritus clouds float around in the pico reef and also in the cleaning bowl? Let's try that next water change if you will.

 

[Mihai]

Things that I know:

- there is no significant front lighting source (it's behind a wall, no direct light from any window, rarely some light from the kitchen lights, but very very little compared with what is on top of it). I'd assume that it's not O2 but rather CO2.

- the rock does get covered either with some brown or with some green slime/film that I can remove with a paintbrush. You can see it in the pic right above and a bit to the right of the GSP patch in the middle of the pic.

- regarding the acro and the montiporas they didn't really grow any more than 1mm at the best in the last 4 months. They just changed color to brown (both montis are green and the acro is purple in the display) and hanged on. I was hoping to get a bit of color with the upgrade in light.

To do list:
- pH readings
- swishing LR in clean SW. I assume that detritus/algae will come off (it does when I use a paintbrush to put it in suspension before water changes). I'm a bit afraid I'm going to shock the corals/pods in the process. Furthermore, in the small cave in the middle I have two small Pseudocorynactis sp. corals that are not attached to almost anything and I'd hate to lose them (they reproduce rather slow).

Thanks for the help,
Mihai

 

[brandon4291]

Can't wait to see those results Mihai, that should help narrow it down. Now that I re-read your post, I don't see any extra additions of calcium and alk...maybe it's your water changes handling that re-addition? Even though your tank isn't heavily stocked to the brim, it's aged, and even with that zero nitrate reading (which kinda throws me off a little) I would think it needs alternate-day (or something close to it) dosing of liquid calcium and alk, just to keep them both at nice/high levels. I see your SPS growing but it may be a little slow by your account, I believe this would contribute. Specifically, I can replicate that very algae bloom in my tank (even well after the cycle) within a week-- not by adjusting the bioloading, but by ceasing the addition of the dosers to my system. This has happened twice when I went out of town before...I came home to a diatom?browncyano? thin mat on the walls when it went about 5 days without a dose of either chemical. in systems with dense corals and rock I think the process speeds up considerably, but I try and picture the trends going on in your system never being dosed and this also registers as a contributor for me. I cannot draw the link biologically between the two occurrences, but if I don't dose my tank regularly I get similar blooms that in my opinion aren't tied directly to the bioload. Still brainstorming!!

 

[Mihai]

That's right: I always assumed that with such an aggresive water change schedule I'll never even need supplementations of Ca and Alk (not even close). I may underestimate the ratio of corals to the water volume so I'll check that as well.

M.

 

[Mihai]

OK, I got mixed results: at the end of the day I have:

pH = 8.4 (color test not probe, can be anywhere 8.2 - 8.6)
Alk = 2.4 meq (just a tad too low)
Ca = 360 - quite a bit too low.

I thought that larger pH means larger the Alk. Also, if Ca is low, Alk should be low... I really don't get it!

Do you think that I need to supplement?
M.